I just bought a brand new high end pc, but it came with 21h2, when i try to upgrade to 25h2 using the windows 11 installation assistant from microsoft website, the first step of 3, which is downloads to 100% without problem and so is the 2nd step but on the 3rd step, which is installing, my pc restarts at 88% percent at the installing. ive seen some reddit posts saying that it should restart and complete it itself, however it doesnt open the installation assistant app by itself after restarting, i wonder what to do about it, and plus i never got offered any update or whatever from my pc's default windows update settings screen, it just says that its missing security updates, thats why im trying to upgrade from 21h2 to 25h2 to fix the problem and recieve the important updates on time The most successful method to install version 25H2 is to use the Windows 11 ISO, which is the bottom (3rd) link on the Microsoft web page. Please ensure you download the ISO in the same language as you use for the Windows UI, follow the steps, this is then not like re-installing Windows, it is just like an update and your personal files, settings and installed software will not be affected. Click this link: https://www.microsoft.com/software-download/windows11 to download the Windows 11 ISO When the ISO file completes downloading Disconnect from the Internet Disconnect all external devices with the exception of a mouse or keyboard. Temporarily disable any 3rd party Anti-virus you may have installed Then, in Windows File Explorer, double click the ISO and then run Setup.exe and select the Install option. Very Important - ensure you select the option to keep your files and apps.

Imangali 10A • 20 Reputation points 2025-10-13T08:19:01.31+00:00 does having a really old version such as 21h2 affect the process or not? 0 votes Report does having a really old version such as 21h2 affect the process or not? DaveM121 • 919.3K Reputation points • Independent Advisor 2025-10-13T08:20:37.1033333+00:00 No that should not affect the update process, you should be able to go directly from version 21H2 to version 25H2 using the ISO method. 1 vote Report No that should not affect the update process, you should be able to go directly from version 21H2 to version 25H2 using the ISO method. Imangali 10A • 20 Reputation points 2025-10-13T08:22:03.37+00:00 does using the installation assistant version delete all ur current files such as the games donwloaded which are 200-400gb 0 votes Report does using the installation assistant version delete all ur current files such as the games donwloaded which are 200-400gb DaveM121 • 919.3K Reputation points • Independent Advisor 2025-10-13T08:24:14.11+00:00 No, using the Installation Assistant or the ISO method does no delete your current files, ensure you choose the option to keep your files and apps at the start of the process. 1 vote Report No, using the Installation Assistant or the ISO method does no delete your current files, ensure you choose the option to keep your files and apps at the start of the process. Bruce Baker-Johnson • 0 Reputation points 2026-06-04T14:31:35.5233333+00:00 Clicking on setup.exe it aske how to open. I used Explorer and 'Run as administrator' . Gets to the checking the machine stage and then says "Sorry" and Setup as encountered a Critical Error ... try again . (0x 80070003 - 0x40008) . Just keeps doing that. 0 votes Report Clicking on setup.exe it aske how to open. I used Explorer and 'Run as administrator' . Gets to the checking the machine stage and then says "Sorry" and Setup as encountered a Critical Error ... try again . (0x 80070003 - 0x40008) . Just keeps doing that. 0 additional answers